Injection pump regulating structure



July 9, 1957 H. HELMscHRo-r ETAL INJECTION PUMP REGULATING STRUCTURE Filed llay 16, 1955 MQAMSMW Uited States Patent' 2,798,469 INJECTION PUMP REGULATING STRUCTURE Hans Helmschrott, Stuttgart-Unterturkheini, Max Hurst, Stuttgart, and Johannes Weber, Stuttgart-Feuerbach, Germany, assignors to Robert Bosch G. m. b. H., Stuttgart, Germany Application May 16, 1955, Serial No. 508,624

Public Law 619, August 23, 1954, Patent expires October 1, 1968 eclaims. (c1. 12s-14o) :The present invention relates to injection pumps and more particularly to a structure for automatically regulating the operation of injection pumps of the type used in Diesel engines, for example.

With pumps of this type it is conventional to provide a stop in the regulating structure of the pump for determining the full load position of the injection pump. However, with the known structures this stop is almost inaccessible and great inconvenience is involved in adjusting the stop. Furthermore, when a conventional engine of the above type operates at full load and then starts to operate at less than full load, too much fuel is supplied by the injection .pump until the regulating structure thereof adjusts itself to operating at less than full load, so that `during transition from full to less than full load there is a period of time during which the operation is inetiicient and uneconomical.

One of the objects of the present invention is to provide an injection pump with a regulating structure which includes a stop of the above type which is easily accessible and which can be adjusted without any inconvenience.

Another object of the present invention is to provide an exceedingly simple stop structure capable of .allowing more than the full load amount of fuel to be delivered by the pump for starting the engine.

Also, it is an object of the present invention to provide an injection pump regulating structure which includes an exceedingly simple means for compensating for the excessive amount of fuel which tends to be drawn into the engine when the engine speeds up during the transition from full load to less than full load.

`With the above objects in view, the present invention mainly consists of an injection pump which includes a housing shiftably carrying a first control means for `regulating the amount of fuel delivered by the pump. A second pressure sensitive Icontrol means responsive to the difference between atmospheric pressure and the pressure in the intake manifold is operatively connected to the first control means for positioning the latter in accordance with this pressure differential. A yieldable st-op means is carried by the housing at an outer part thereof for engaging one of these control means to determine the full load position of the iirst and second control means. The second control means includes a spring means urging the second control means in a direction tending to shift the lirst control means to increase the amount of fuel delivei'ed by the pump, and the second control means also includes a yieldable resilient means for opposing the force of the spring means. This yieldable resilient means is engaged by the above yield-able stop means and is stressed by this stop means in the full load position of the first and 'second control means to oppose the force of this spring means in this full load position.

IThe novel features which are considered `as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together` with ladditional -objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the 'accom panying drawings, in which:

Figure l is a fragmentary front end view of that part of an injection pump which houses the regulating structure thereof;

. Figure 2 is a fragmentary sectional view `taken along line lI-II of Figure l in the direction 0f the arrows; and

Figure 3 is a fragmentary sectional view taken along line lI'I-III of Figure l in the direction of the arrows.

Referring now -to the drawings, the injection pump of the invention includes a housing portion 5 fragmentarily illustrated in the drawings `and housing purely conventional parts of an injection pump, these parts including a plurality of pistons and a cam shaft for reciprocating these pistons. As is well known, the pistons of such an injection pump are formed with helical grooves and may be angularly adjusted about their axes, respectively, to regulate the amount of fuel delivered by the injection pump when the pistons are reciprocated. The angular position of lthe pistons about their axes, respectively, is adjusted in a known way by a control means in the form of a rod 6, part of which is shown in Figures 2 and 3. A housing portion 10 is connected to the right wall of housing 5, as viewed in Figure 2, -to form together with the housing 5 an independent housing which shiftably supports the control means 6, this control means 6 extending `through the wall of housing 5 into 'the latter for adjusting the pistons.

A pin 7 is fixed to the f-ree end of rod 6 which is located within the housing 10, and `this pin 7 extends laterally Yfrom the rod 6, as indicated most clearly in Figure 3. The pin 7 extends through a pair of aligned openings of a sleeve 8 with a fairly close t so that the sleeve 8 neces- `sarily shifts together with the rod 6.

Sleeve 8 is fixed to a flexible diaphragm 9 which is clamped between a cover 11 of the housing 1t) and the remainder of the housing 1t) to divide the .interior of the housing 10 into a pair of chambers. The chamber to the right of diaphragm 9, as viewed in Figure 2, communicates through the ytube 12 -with the intake manifold of the engine downstream of the butterfly' valve therein which is adjusted by yoperation of the `accelerator in a known way. The lhousing 1t) is formed on the other side of diaphragm 9 with a hollow rib portion 21 formed with a slot 22, and the rib portion 21 is made of a springy metal, for example, so that the Slot 22 divides rib portion 21 into a pair of springy portions which may be drawn together, a screw means 23 being shown in Figures l and 2 for this purpose. The screw means 23 is in the form of a `screw member extending freely through a bore in the left part of rib portion 21, as viewed in Figure l, with the head of the screw 23 engaging the left face of rib portion 21, as viewed in Figure l, and the screw member 23 extends across the slot 22 into threaded `engagement with the 4right part of the rib portion 21 of the housing 10. The slot 22 additionally serves the purpose of placing the chamber at the left of diaphragm 9, as viewed in Figure 2, in communication with the outer atmosphere, so that the diaphragm 9 responds to the pressure differential between atmospheric pressure and the pressure within the intake manifold.

A spring 2i) within the housing il@ engages the diaphragm 9 to urge the latter toward the left, as viewed in Figure 2, so that the spring 20 tends to shift control means 6 to the left in a direction which increases the amount of fuel delivered to the injection pump. Within the sleeve 8 is located a spring 25 which engages the right end wall of sleeve S, as viewed in Figure 2, and a pin 27 is slidaole within the sleeve 8 and lengages the pin 7 as indicated in Figures 2 and 3, this pin 27 being formed with a transverse elongated opening 25 through which the pin .7 ex#` tends with a predetermined clearness, as indicated in Figures 2 and 3. Thus, the diaphragm 9, together with all of the parts engaging and carried by the same, form a pressure sensitive control means which is operatively connected to the control means 6 by the pin 7.

The housing 10 further supports for turning movement a shaft 13 which extends outwardly beyond the housing 19 and which has its left end, as viewed in Figure l, fixed to a lever 14 which may be manually turned in a known way by the operator through a suitable linkage. The two armed lever 15 is fixed to the shaft i3 within the housing itl for turning movement together with the shaft 13, and the upper arm of lever 15, as viewed in Figure 2, has a free end in engagement with the left end face of the pin 27, as viewed in Figure 2. A wire spring 17 is coiled about the shaft 13, with one end in engagement with a stationary pin 24 carried by the housing 10, and has its opposite end in engagement with the upper arm of lever l5, as viewed in Figure 2, so that the spring 17 urges the lever 15 in a counterclockwise direction, as viewed in Figure 2. The other, lower arm of lever 15, as viewed in Figure 2, engages a stop member 16 which is slidably supported by a sleeve 19 which threadedly engages a threaded bore of the rib 21 and which extends across the slot 22. The left end of the sleeve 19 is formed with an inwardly extending annular ange engaging a collar 26 fixed to the stop 16 so as to limit movement of the stop le to the left, as viewed in Figure 2. This collar 26 may also be in the form lof an annular flange integral with the stop 16. The coil spring lwithin the housing 19 engages the collar 26 and the right end wall of sleeve 19, as viewed in Figure 2, to urge the collar 26 to the left, as viewed in Figure 2, into engagement with the annular ange at the left end of sleeve 19, as viewed in Figure 2. The

right end wall of sleeve 19, as viewed in Figure 2, is formed with a slot to receive a screw driver so that by turning of the sleeve 19 its axial position with respect to the rib 2l may be adjusted, and the screw means 23 may be tightened to fix the sleeve 19 in its adjusted position.

The stop 16, together with the structure carrying the same, and the lever 15, together with the parts associated therewith, form a yieldable stop means which engages the pin 27 to determine the full load position of the regulating parts of the invention. Thus, in the position of the parts shown in Figure 2, the fuel supply has reached the maximum full load value determined by the engagement between the pin 27 and lever 15. The spring 18 is strong enough to overcome the force of all of the other springs so that the stop 16 is maintained in the position indicated in Figure 2, and thus the control structure cannot move beyond the position of Figure 2 to increase the amount of fuel. Therefore, as the operator increases the acceleration approaching full load conditions, the vacuum in the intake manifold will decrease, and the spring 20 will be capable of shifting the diaphragm 9 to the left, as viewed in Figure 2, until pin 27 engages lever 15 and places the structure in its full load operating position.

lf it is desired to stop the engine, the lever llt is manually turned by the operator in a position which turns shaft 1.3 and lever 15 in a clockwise direction, as viewed in Figure 2, to the position C, and in this position of the parts, the engine does not receive enough fuel to continue its operation so that the engine stops. Upon release of the lever i4, the spring 17 immediately returns the lever 15 to the position A shown in Figure 2, which is the full load position, and of course the spring Ztl can also return the control structure to the position shown in Figure 2. When operating at less than full load at high vacuum in lthe intake manifold, the pressure differential, acting on the diaphragm 9, will be sufficient to shift pin 27 and rod 6 to the right, as viewed in Figure 2, so that pin 27 moves out of engagement with the lever 15 which remains under these conditions in the position shown in Figure 2.

When it is desired to start the engine, the lever 14 is turned by the operator in a direction which turns shaft Cil 13 and lever 15 in a counterclockwise direction, as viewed in Figure 2, to the position B shown in Figure 2, and in this position of the parts, more than the fuel supply at full load is provided, so that the engine may be easily started. During turning ofthe lever 15 to the position B, the springy 18 is compressed. The spring 2t) is capable of' urging the diaphragm 9 to the left, as viewed in Figure 2,v so that the diaphragm, together with the rod 6, can follow the movement of lever 15 to the position B. Upon release of the lever 14, the spring 1S, which is stronger than the forces exerted by springs 20 and 17, returns the parts to the positions shown in Figure 2, and during the subsequent operation of the engine at less than full load, the diaphragm 9 shifts to the right, as viewed in Figure 2, to move the pin 27 away from the lever 15.

When full load operating conditions are approached, the diaphragm 9 is moved to the left, as viewed in Figure 2, and the pin 27 engages the lever 15. Figure 3 shows the parts in the position they have just before the pin 27 engages the lever 15 under these conditions. After the pin 27 engages lever 15, the sleeve 8, together with diaphragm 9 and rod 6 as well as pin 7, can continue to move to the left as viewed in Figure 2, while pin 27 remains stationary within the limits provided by the opening 28, and the parts then assume, when full load position is reached, the position shown in Figure 2. It will be noted that in this position the spring 25 has been compressed and therefore the force of this spring opposes the force of the spring 20. As a result, the vacuum required to shift the diaphragm 9 to the right, as viewed in Figure 2, is lessened by the added force derived from the compression of spring 25, and thus the force necessary to move the diaphragm 9 to the right, as viewed in Figure 2, is less than that which is required to overcome the force of spring 20 alone. Thus, when the engine operates at full load, as when it is driving a vehicle up a hill, the parts will have the position shown in Figure 2. When the engine is required to overcome less than full load, as when the top of such a hill is reached, the engine starts to speed up, and such operation would normally result in drawing too much fuel intov the engine during this transition period. However, because of the compression of spring 25, it is easier for the diaphragm 9 to move in the stop direction indicated in Figure 2 which decreases the fuel delivered to the engine, and therefore during this transition period, with the arrangement of the invention, the spring 25 adds its force to that of the vacuum and guarantees that there is no lag in the movement of diaphragm 9, and thus the undesirable supplyingof too much fuel is avoided. As soon as the pin 7 moves to the right end of opening 28, as viewed in Figure 2, the full force of the spring 20 again acts on the diaphragm and the parts continue to operate without the Icompensation provided by spring 25.

lt will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of injection pumps differing from the types described above.

While the invention has been illustrated and described as embodied in a regulating structure for injection pumps, it is not intended to be limited to the details shown, since various modications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by `applying `current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential Vcharacteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and arev intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. In an injection pump, in combination, support means; first control means shiftably carried by said support means for regulating the amount of fuel delivered by the pump; second pressure-sensitive control means responsive to the difference between atmospheric pressure and the pressure in an intake manifold and operatively connected to said first control means for positioning the latter in accordance with said pressure differential, said second control means including a spring means urging said second control means in a direction tending to shift said first control means to increase the amount of fuel delivered by the pump and said second control means including a yieldable resilient means for opposing the force of said spring means; and yieldable stop means 'carried by said support means for engaging said yieldable resilient means to determine the full load position of said first and second control means and for stressing said yieldable resilient means to oppose the force of said spring means when said first and second control means are in said full load position.

2. In an injection pump, in combination, support means; first control means shiftably carried by said support means for regulating the amount of fuel delivered by the pump; second pressure-sensitive control means responsive to the difference between atmospheric pressure and the pressure in an intake manifold and operatively connected to said first control means for positioning the latter in accordance with said pressure differential, said second control means including a spring means urging said second control means in a direction tending to shift said first control means to increase the amount of fuel delivered by the pump and said second control means including a sleeve, a spring in said sleeve for opposing said spring means, and a pin slidable in said sleeve and enga ging said spring for compressing the latter to oppose said spiing means; and yieldable stop means carried by said support means for engaging said pin to determine the full load position of said first and second control means and for compressing said spring to oppose said spring means when said first and second control means are in said full load position.

3. In an injection pump, in combination, support means; first control means shiftably carried by said support means for regulating the amount of fuel delivered by the pump; second pressure-sensitive control means responsive to the difference between atmospheric pressure and the pressure in an intake manifold and operatively connected to said rst control means for positioning the latter in accordance with said pressure differential, said second control means including a spring means urging said second control means in a direction tending to shift said first control means to increase the amount of fuel delivered by the pump and said second -control means including a sleeve, a spring in said sleeve for opposing said spring means, and a first pin slidable in said sleeve and engaging said spring for compressing the latter to oppose said spring means, said first control means being in the form of an elongated rod and said second control means being operatively connected to said first control means by a second pin fixed to said rod, connected to said sleeve, and engaging said first pin for limiting the movement thereof in said sleeve; and yieldable stop means carried by said support means for engaging said pin to determine the full load position of said first and second control means and for compressing said spring to oppose said spring means when said first and second control means are in said full load position.

4. In an injection pump, in combination, support means; first control means shiftably carried by said sup port means for regulating the amount of fuel delivered by the pump; second pressure sensitive control means responsive to the difference between atmospheric pressure and the pressure in an intake manifold and operatively connected to said first control means for positioning the latter in accordance with said pressure differential, said second control means including a spring means urging said second control means in a direction tending to shift said first control means to increase the amount of fuel delivered by the pump and said second control means including a sleeve, a spring in said sleeve for opposing said spring means, and a first pin slidable in said sleeve and engaging said spring for compressing the latter to oppose said spring means, said first pin being formed with an elongated transverse opening, and said first control means being in the form of an elongated rod and said second control means being operatively connected to said first control means by a second pin fixed to said rod, connected to said sleeve, and extending with clearance through said opening of said first pin for limiting the movement thereof in said sleeve; and yieldable stop means carried by said support means for engaging said pin to determine the full load position of said first and second control means and for compressing `said spring to oppose said spring means when said first and second control means are in said full load position.

5. In an injection pump, in combination, a housing; a yieldable diaphragm carried by said housing in the interior thereof; a first spring located in said housing and engaging said diaphragm for urging the latter in one direction; a sleeve fixed to said diaphragm and extending from a face thereof which is directed away from said first spring; a second spring in said sleeve at an end thereof adjacent said first spring; a first pin slidable within said sleeve and engaging said second spring, said first pin being formed with an elongated transverse opening passing therethrough; a second pin extending through said sleeve and with clearance through said opening of said first pin; a rod fixed to said second pin and slidably carried by said housing so that said rod shifts With said diaphragm; and yieldable stop means carried by said housing and engaging said rst pin for determining the full load position of said rod.

6. ln an injection pump, in combination, support means; first control means shiftably carried by said support means for regulating the amount of fuel delivered by the pump; second pressure-sensitive control means responsive to the difference between atmospheric pressure and the pressure in an intake manifold and operatively connected to said first control means for positioning the latter in accordance with said pressure differential; yieldable stop means carried by said support means at an outer part thereof for engaging one of said control means to determine the full load position of said first and second control means; and moving means operatively connected to said yieldable stop means for moving the latter together with said first and second control means to a position where said first control means provides less than the amount tof fuel required for idling in order to stop an engine carrying the injection pump.

References Cited in the le of this patent UNITED STATES PATENTS 2,209,321 Colell July 30, 1940 FOREIGN PATENTS 436,126 Great Britain Oct. 4, 1935 501,088 Great Britain Feb. 2.1, 1939 826,665 Germany Ian. 3, 1952 

